CN220368462U - Overvoltage protection circuit - Google Patents
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- CN220368462U CN220368462U CN202323472672.6U CN202323472672U CN220368462U CN 220368462 U CN220368462 U CN 220368462U CN 202323472672 U CN202323472672 U CN 202323472672U CN 220368462 U CN220368462 U CN 220368462U
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Abstract
The utility model relates to an overvoltage protection circuit, which relates to the technical field of electronics and comprises an on-off control module, a power supply conversion module, a sampling module, an amplifying module, a switch control module and a drive control module, wherein the drive control module is used for outputting a control signal for disconnecting an input power supply from a load circuit when the voltage of the load circuit is higher than a second reference voltage; when the voltage of the load circuit is lower than the second reference voltage, the drive control module outputs a control signal for communicating the input power supply with the load circuit. The primary amplifying module and the feedback circuit are adopted to monitor the voltage of the load circuit, the working state of the field effect transistor is controlled according to the voltage value of the load voltage, the voltage of the load circuit is regulated within a certain overvoltage range, the technical effect of normal operation of the load circuit is ensured, the input power supply and the load circuit are cut off within the overvoltage range, and the effect of protecting the load circuit is achieved.
Description
Technical Field
The utility model relates to the technical field of an abnormality protection circuit, in particular to an overvoltage protection circuit.
Background
Overvoltage protection, also called voltage protection, is a protection mode that disconnects the power supply or reduces the voltage of the controlled device when the voltage exceeds a predetermined maximum value.
Overvoltage protection circuits commonly used in the market at present generally adopt an overvoltage protection chip, a drive conversion protection circuit and a switching power supply type protection circuit. The drive conversion protection circuit controls the state of the MOS tube by using two sets of drive circuits, and when a surge enters, the MOS tube is switched from normal working drive to overvoltage protection drive state, so that overvoltage protection is realized; when the MOS tube is in a closed state, the energy storage circuit at the output end of the switching power supply type protection circuit provides voltage output below 36V so as to realize overvoltage protection.
However, in the process of implementing the technical scheme of the utility model in the embodiment of the application, the inventor of the application finds that at least the following technical problems exist in the above technology:
the overvoltage protection chip has limited application scenes and cannot be applied to all overvoltage protection scenes; the drive conversion protection circuit has the advantages that as two sets of drive circuits and control circuits exist, the drive conversion protection circuit has the advantages of more components, large circuit area and high cost, and cannot meet the application scenes of products with small volume, low power and low cost; because the energy storage circuit inside the switch power supply type protection circuit can use a larger energy storage capacitor or inductance, the whole circuit is larger, and when the MOS tube is in a closed state, the load capacity of the power supply is greatly reduced because the energy of the power supply is completely from the energy storage circuit at the output end, the normal work of a load can be influenced, and for a high-power supply loop, the impact current in the whole loop can be increased by the charging of the energy storage part, so that the negative influence is caused.
Disclosure of Invention
In order to solve the technical problems, the embodiment of the application provides an overvoltage protection circuit, which comprises a power supply conversion module, a primary amplifying module, a driving control module and an on-off control module;
the power supply conversion module is connected with an input power supply, and is used for converting the input power supply voltage into various reference voltages and providing the reference voltages for the primary amplification module and the drive control module;
the primary amplifying module is connected with the power supply conversion module, the load circuit and the drive control module and is used for comparing the voltage of the load circuit with the reference voltage and providing a comparison result to the drive control module;
the first input end of the driving control module is used for inputting the comparison result, the second input end is used for inputting the reference voltage, the third input end is used for inputting the load circuit voltage, and the output end is connected with the on-off control module;
the first end of the on-off control module is connected with the input power supply, the second end of the on-off control module is connected with the load circuit, and the third end of the on-off control module is connected with the drive control module;
when the voltage of the load circuit is higher than the rated highest voltage, the drive control module outputs a control signal for controlling the on-off control module to disconnect the input power supply from the load circuit;
when the voltage of the load circuit is higher than the threshold voltage, the drive control module outputs a control signal for controlling the on-off control module to reduce the voltage of the load circuit.
Further, the power conversion module includes:
a power supply circuit for supplying a constant voltage to the drive control module;
and the voltage conversion circuit is connected with the power supply circuit, the primary amplifying module and the driving control module, and is used for converting the constant voltage into a reference voltage and providing the reference voltage for the primary amplifying module and the driving control module.
Further, the power supply circuit comprises a power supply conversion chip U3, a resistor R10, an inductor L2 and a diode D4;
the inductor L2 is connected in series between the input power supply and the positive electrode of the diode D4, and the negative electrode of the diode D4 is connected with the output end of the power supply circuit;
the power supply pin VIN of the power supply conversion chip U3 is connected with the input power supply, the enabling pin SHDN is connected with the input power supply through a resistor R10, the output pin SW is connected between the inductor L2 and the anode of the diode D4, the grounding pin GND is grounded, and the feedback pin FB is used for inputting the output end voltage of the power supply circuit.
Further, the voltage conversion circuit comprises a resistor R17, a resistor R20, a resistor R21 and a voltage regulator Q5;
the resistor R17, the resistor R20 and the resistor R21 are sequentially connected in series between the output end and the grounding end of the power supply circuit;
the sampling end 1 of the voltage regulator Q5 is connected with the common end of the resistor R20 and the resistor R21, and the control end 2 is connected with the common end of the resistor R17 and the resistor R20;
the common terminal of the resistor R20 and the control terminal 2 of the voltage regulator Q5 is used as an output terminal of the voltage conversion circuit for outputting the reference voltage.
Further, the primary amplifying module comprises an operational amplifier OP1, a resistor R11, a resistor R12, a resistor R13, a resistor R16, a capacitor C5 and a capacitor C7;
the resistor R11 and the resistor R13 are sequentially connected in series between the load circuit and the grounding end;
the power end of the operational amplifier OP1 is connected with the output end of the voltage conversion circuit, the ground is grounded, the non-inverting input end of the operational amplifier OP1 is connected with the output end of the voltage conversion circuit through the resistor R12, the inverting input end of the operational amplifier OP1 is connected with the common end of the resistor R11 and the resistor R13, and the output end of the operational amplifier OP is connected with the driving control module through the resistor R16;
the capacitor C5 is connected between the output end of the voltage conversion circuit and the grounding end;
the capacitor C7 is connected between the output terminal of the operational amplifier OP1 and the ground terminal.
Further, the drive control module comprises a feedback circuit and a control circuit;
the feedback circuit is connected with the load circuit, the voltage conversion circuit and the control circuit and is used for outputting a high level to the control circuit when the voltage of the load circuit is higher than the rated highest voltage and outputting a low level to the control circuit when the voltage of the load circuit is lower than the rated highest voltage;
the control circuit is connected with the power supply circuit, the feedback circuit, the primary amplifying module and the on-off control module and is used for inputting a low level to the on-off control module when the voltage of the load circuit is higher than the rated highest voltage and inputting a high level to the on-off control module when the voltage of the load circuit is higher than the threshold voltage.
Further, the feedback circuit comprises a resistor R24, a resistor R27, a resistor R28, a resistor R29, a triode Q6 and a triode Q7;
the resistor R24 and the resistor R27 are sequentially connected in series between the grounding end and the load circuit;
the base electrode of the triode Q6 is connected with the common end of the resistor R24 and the resistor R27, the emitter electrode is grounded, the collector electrode is connected with one end of the resistor R28, and the other end of the resistor R28 is connected with the voltage conversion circuit;
the base electrode of the triode Q7 is connected with the resistor R28 and the common end of the collector electrode of the triode Q6 and the resistor R28, the emitter electrode is connected with one end of the resistor R29, the collector electrode is connected with the control circuit, and the other end of the resistor R29 is connected with the voltage conversion circuit.
Further, the control circuit comprises an operational amplifier OP2, a resistor R22, a resistor R25, a resistor R26, a resistor R30, a capacitor C9 and a capacitor C10;
the power end of the operational amplifier OP2 is connected with the output end of the power circuit, the ground is grounded, the non-inverting input end of the operational amplifier OP2 is connected with the primary amplifying module through the resistor R25, the output end of the operational amplifier OP2 is connected with the on-off control module through the resistor R30, the resistor R12 and the resistor R26 are sequentially connected in series between the output end of the operational amplifier OP2 and the ground, and the inverting input end of the operational amplifier OP2 is connected with the common end of the resistor R12 and the resistor R26;
one end of the capacitor C9 is connected between the output end of the power supply circuit and the grounding end;
the capacitor C10 is connected between the output terminal of the operational amplifier OP2 and the ground terminal.
Further, the on-off control module adopts a field effect transistor Q2, a drain electrode of the field effect transistor Q2 is used as a first end of the on-off control module, a source electrode of the field effect transistor Q2 is used as a second end of the on-off control module, and a gate electrode of the field effect transistor Q2 is used as a third end of the on-off control module.
One or more technical solutions provided in the embodiments of the present application at least have the following technical effects or advantages:
the primary amplifying module and the feedback circuit are adopted to monitor the voltage of the load circuit, the working state of the field effect transistor is controlled according to the voltage value of the load voltage, and the field effect transistor is controlled to enter a saturated conduction state during normal operation, so that the effect of transmitting the voltage to the load circuit by an input power supply is realized; when overvoltage enters, the voltage of the load circuit is higher than the threshold voltage, and the field effect transistor is controlled to enter a linear working area to inhibit signals input by an input power supply to the load circuit, so that the voltage of the load circuit is kept stable; when the load circuit is higher than the rated highest voltage, the field effect transistor is controlled to be disconnected, the input power supply is not conducted with the load circuit, the effect of protecting the load circuit is achieved, the voltage of the load circuit is regulated within a certain overvoltage range, the normal operation of the load circuit is guaranteed, and when the voltage exceeds the overvoltage range, a voltage signal between the input power supply and the load circuit is cut off, and the effect of protecting the load circuit is achieved.
2. The voltage of the input field effect transistor is regulated by adopting linear negative feedback regulation and adopting an operational amplifier, so that the voltage of the load circuit is controlled, the traditional switch switching mode is replaced by the operational amplifier, the electromagnetic interference of the circuit is reduced, and the protection effect of the overvoltage protection circuit is realized.
3. The primary amplifying module and the feedback circuit are adopted to input the voltage signals of the load circuit into the control circuit respectively, so that the control circuit can control the working state of the field effect transistor effectively, synchronous matching with other circuit modules is not needed, the length of a control loop is reduced, and the response speed is further improved.
4. The field effect transistor is adopted, so that the voltage signal of the input power supply input load circuit is disconnected when the voltage of the load circuit exceeds the rated highest voltage, the effect of protecting the load circuit is achieved, and the small-power protection device is also suitable for small-power protection scenes, the technical problem that the application scenes of the overvoltage protection circuit are limited is effectively solved, and the application requirements under different scenes are met.
Drawings
FIG. 1 is a block diagram of an overvoltage protection circuit in one embodiment;
FIG. 2 is a block diagram of an overvoltage protection circuit in one embodiment;
FIG. 3 is a circuit diagram of a power circuit in one embodiment;
FIG. 4 is a circuit diagram of a voltage conversion circuit in one embodiment;
FIG. 5 is a circuit diagram of a primary amplifying module in one embodiment;
FIG. 6 is a circuit diagram of a feedback circuit in one embodiment;
FIG. 7 is a circuit diagram of a control circuit in one embodiment;
FIG. 8 is a circuit diagram of an on-off control module in one embodiment.
Detailed Description
In order to better understand the above technical solutions, the following detailed description will be given with reference to the accompanying drawings and specific embodiments, and it is apparent that the described embodiments are only some, but not all, examples of the present utility model. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the utility model, its application, or uses. All other embodiments, which can be made by a person skilled in the art without any inventive effort, are intended to be within the scope of the present utility model, based on the embodiments of the present utility model.
Please refer to fig. 1.
The embodiment of the application provides an overvoltage protection circuit, which comprises a power supply conversion module 100, a primary amplifying module 200, a driving control module 300 and an on-off control module 400;
the power conversion module 100 is connected to an input power source 28V + _ IN for converting the input power source voltage into various reference voltages and providing the reference voltages to the primary amplification module 200 and the driving control module 300;
a primary amplifying module 200 connected to the power conversion module 100, the load circuit 28v+ _out, and the driving control module 300 for comparing the load circuit voltage with the reference voltage VB2 and providing the comparison result op1_o to the driving control module 300;
the first input end of the driving control module 300 is used for inputting the comparison result OP1_O, the second input end is used for inputting the reference voltage, the third input end is used for inputting the load circuit voltage 28V+ _OUT, and the output end DR1 is connected with the on-off control module 400;
the first end of the on-off control module 400 is connected with an input power supply 28V+ IN, the second end is connected with a load circuit 28V+ OUT, and the third end is connected with the driving control module 300;
wherein, when the load circuit voltage is higher than the rated highest voltage, the drive control module 300 outputs a control signal for controlling the on-off control module 400 to disconnect the input power supply 28 v_in from the load circuit 28 v_out;
when the load circuit voltage is higher than the threshold voltage, the driving control module 300 outputs a control signal for controlling the on-off control module 400 to reduce the load circuit voltage.
In conjunction with fig. 2.
In some embodiments, the power conversion module 100 includes:
a power supply circuit 110 for supplying a constant voltage VB1 to the drive control module;
the voltage conversion circuit 120 is connected to the power supply circuit 110 and the drive control module 300, and is configured to convert the constant voltage VB1 into the reference voltage VB2 and supply the same to the primary amplifying module 200 and the drive control module 300.
In some embodiments, the drive control module 300 includes a feedback circuit 320 and a control circuit 310;
the feedback circuit 320 is connected to the load circuit 28 v_out, the voltage conversion circuit 120, and the control circuit 310, and is configured to output a high level to the control circuit 310 when the load circuit voltage is higher than the rated maximum voltage, and output a low level to the control circuit 310 when the load circuit voltage is lower than the rated maximum voltage;
the control circuit 310 is connected to the power circuit 110, the feedback circuit 320, the primary amplifying module 200 and the on-off control module 400, and is configured to input a low level to the on-off control module 400 when the voltage of the load circuit is higher than the rated maximum voltage, and input a high level to the on-off control module 400 when the voltage of the load circuit is higher than the threshold voltage.
In conjunction with fig. 3.
In some embodiments, the power circuit 110 includes a power conversion chip U3, a resistor R10, an inductance L2, and a diode D4;
the inductor L2 is connected IN series between the input power supply 28V+ IN and the positive electrode of the diode D4, and the negative electrode of the diode D4 is connected with the output end of the power supply circuit 110; specifically, the output terminal of the power supply circuit 110 outputs a constant voltage VB1.
The power supply pin VIN of the power conversion chip U3 is connected to the input power supply 28v+ _in, the enable pin SHDN is connected to the input power supply 28v+ _in through the resistor R10, the output pin SW is connected between the inductor L2 and the anode of the diode D4, the ground pin GND is grounded, and the feedback pin FB is used for inputting the output voltage VB1 of the power supply circuit 110.
In conjunction with fig. 4.
In some embodiments, voltage conversion circuit 120 includes a resistor R17, a resistor R20, a resistor R21, and a voltage regulator Q5;
the resistor R17, the resistor R20 and the resistor R21 are sequentially connected in series between the output end of the power supply circuit 110 and the ground end;
the sampling end 1 of the voltage regulator Q5 is connected with the common end of the resistor R20 and the resistor R21, and the control end 2 is connected with the common end of the resistor R17 and the resistor R20;
the common terminal of resistor R20 and control terminal 2 of voltage regulator Q5 serves as the output terminal of voltage conversion circuit 120 for outputting reference voltage VB2.
In conjunction with fig. 5.
In some embodiments, the primary amplification module 200 includes an operational amplifier OP1, a resistor R11, a resistor R12, a resistor R13, a resistor R16, a capacitor C5, and a capacitor C7;
the resistor R11 and the resistor R13 are sequentially connected in series between the load circuit 28V+ OUT and the ground terminal;
the power end of the operational amplifier OP1 is connected with the output end of the voltage conversion circuit 120, the ground is grounded, the non-inverting input end is connected with the output end of the voltage conversion circuit 120 through a resistor R12, the inverting input end is connected with the common end of a resistor R11 and a resistor R13, and the output end is connected with the drive control module 300 through a resistor R16;
the capacitor C5 is connected between the output end of the voltage conversion circuit 120 and the ground end;
the capacitor C7 is connected between the output terminal of the operational amplifier OP1 and the ground terminal.
In conjunction with fig. 6.
In some embodiments, feedback circuit 320 includes resistor R24, resistor R27, resistor R28, resistor R29, transistor Q6, and transistor Q7;
the resistor R24 and the resistor R27 are sequentially connected in series between the grounding end and the load circuit 28V+ OUT;
the base electrode of the triode Q6 is connected with the common end of the resistor R24 and the resistor R27, the emitter electrode is grounded, the collector electrode is connected with one end of the resistor R28, and the other end of the resistor R28 is connected with the voltage conversion circuit 120;
the base electrode of the triode Q7 is connected with the common end of the resistor R28 and the collector electrode of the triode Q6 as well as the resistor R28, the emitter electrode is connected with one end of the resistor R29, the collector electrode is connected with the control circuit 310, and the other end of the resistor R29 is connected with the voltage conversion circuit 120.
In conjunction with fig. 7.
In some embodiments, control circuit 310 includes an operational amplifier OP2, a resistor R22, a resistor R25, a resistor R26, a resistor R30, a capacitor C9, and a capacitor C10;
the power end of the operational amplifier OP2 is connected with the output end of the power circuit 110, the ground is grounded, the non-inverting input end of the operational amplifier OP2 is connected with the primary amplifying module through a resistor R25, the output end of the operational amplifier OP2 is connected with the on-off control module 400 through a resistor R30, a resistor R12 and a resistor R26 are sequentially connected in series between the output end of the operational amplifier OP2 and the ground, and the inverting input end of the operational amplifier OP2 is connected with the common end of the resistor R12 and the resistor R26; specifically, DR1 is an output terminal of the control circuit 310.
One end of the capacitor C9 is connected between the output end of the power circuit 110 and the ground end;
the capacitor C10 is connected between the output terminal of the operational amplifier OP2 and the ground terminal.
In conjunction with fig. 8.
In some embodiments, the on-off control module 400 employs a field effect transistor Q2, the drain of the field effect transistor Q2 is used as the first end of the on-off control module 400, the source of the field effect transistor Q2 is used as the second end of the on-off control module 400, and the gate of the field effect transistor Q2 is used as the third end of the on-off control module 400.
Based on all the embodiments described above, the operating principle of the overvoltage protection circuit is as follows:
the power supply circuit 110 converts an input power supply voltage into a constant voltage VB1 through a power supply conversion chip U3, outputs the constant voltage VB1 to the anode of the diode D4 through a pin of the power supply conversion chip U3, and the resistor R17, the resistor R20 and the resistor R21 have voltage division effects, the constant voltage is input into a sampling end of the voltage regulator Q5 after passing through the voltage R17 and the resistor R18, and a reference voltage VB2 is output through the control end 2 after the voltage regulator Q5 is regulated, wherein the constant voltage VB1 is used for supplying power to the driving control module 300, and the reference voltage VB2 is used for supplying power to the primary amplifying module 200 on one hand and is used as a reference voltage of the primary amplifying module 200 and the driving control module 300 on the other hand.
The reference voltage is input into the normal phase input end of the operational amplifier OP1 after being divided by the resistor R12, the load circuit voltage is input into the reverse phase input end of the operational amplifier OP1 after being divided by the resistor R11, the voltage division value of the resistor R11 and the resistor R12 is lower during normal operation, and the operational amplifier OP1 amplifies the higher voltage in the voltage values of the normal phase input end and the reverse input end and then sends the amplified voltage to the driving control module 300 after being divided by the resistor R16; when the overvoltage is entered, the divided voltage values of the resistor R11 and the resistor R12 rise, forming negative feedback, so that the voltage input to the drive control module 300 decreases, thereby decreasing the output voltage of the drive control module 300.
During normal operation, the feedback circuit 320 is not conductive, the feedback circuit 320 inputs a low level to the inverting input terminal of the operational amplifier OP2, the output voltage of the primary amplifying module 200 is divided by the resistor R25 and then is input to the non-inverting input terminal of the operational amplifier OP2, the feedback circuit 320 is formed between the inverting input terminal and the output terminal of the operational amplifier OP2, the voltage of the output terminal of the operational amplifier OP2 is divided by the resistor R26 and then is input to the inverting input terminal of the operational amplifier OP2, the output voltage of the operational amplifier OP2 is amplified by the primary amplifying module 200 and then is input to the gate of the field effect transistor Q2, the field effect transistor Q2 is in a saturated conductive state, and the input power voltage is directly input to the load circuit 28 v_out.
When the overvoltage is in, the voltage of the load circuit is higher than the threshold voltage, and the output voltage of the primary amplifying module 200 is reduced, so that the voltage of the output end of the operational amplifier OP2 is reduced, the field effect transistor Q2 enters a linear region, the input power supply voltage is restrained, and then the input power supply voltage is input into the load circuit 28V < + > OUT, and the voltage of the load circuit is kept stable. The threshold voltage value was 28V.
When the voltage of the load circuit is higher than the rated highest voltage, the voltage division value of the resistor R24 and the resistor R27 is increased, the triode Q6 is conducted, the collector of the triode Q6 becomes low level, the triode Q7 is conducted, at the moment, the feedback circuit 320 inputs the voltage to the negative phase input end of the operational amplifier OP2, the voltage value of the negative phase input end of the operational amplifier OP2 is increased, the operational amplifier OP2 becomes a comparator and outputs low level, the field effect transistor Q2 is in a closed state, the input power supply and the load circuit are not conducted, and the purpose of protecting the load circuit is achieved.
The capacitor C5, the capacitor C7, the capacitor C9 and the capacitor C10 play a role in filtering, so that input and output voltages are ensured to be more stable, and the safety of the circuit is improved.
The technical scheme in the embodiment of the application at least has the following technical effects or advantages:
the primary amplifying module 200 and the feedback circuit 320 are adopted to monitor the voltage of the load circuit, the working state of the field effect transistor is controlled according to the voltage value of the load voltage, and the field effect transistor is controlled to enter a saturated conduction state during normal operation, so that the effect of transmitting the voltage to the load circuit 28V+ OUT by the input power supply 28V+ IN is realized; when overvoltage enters, the voltage of the load circuit is higher than the threshold voltage, and the field effect transistor Q2 is controlled to enter a linear working area to inhibit signals input by the input power supply 28 V_IN to the load circuit 28 V_OUT, so that the voltage of the load circuit is kept stable; when the voltage of the load circuit is higher than the rated highest voltage, the field effect transistor Q2 is controlled to be disconnected, the input power supply 28 V_IN and the load circuit 28 V_OUT are not conducted, the function of protecting the load circuit 28 V_OUT is achieved, the voltage of the load circuit is regulated within a certain overvoltage range, the normal operation of the load circuit 28 V_OUT is ensured, and when the overvoltage range is exceeded, a voltage signal between the input power supply 28 V_IN and the load circuit 28 V_OUT is cut off, and the function of protecting the load circuit 28 V_OUT is achieved.
The voltage of the input field effect transistor Q2 is regulated by adopting linear negative feedback regulation and the voltage of the load circuit is controlled by adopting the operational amplifier OP2, the traditional switch switching mode is replaced by the operational amplifier OP2, the electromagnetic interference of the circuit is reduced, and the protection effect of the overvoltage protection circuit is realized.
By adopting the primary amplifying module 200 and the feedback circuit 320 to input the voltage signals of the load circuit into the control circuit 310 respectively, the control circuit 310 controls the working state of the field effect transistor Q2, and the control circuit does not need to be matched with other circuit modules synchronously, so that the length of a control loop is reduced, and the response speed is further improved.
By adopting the field effect transistor Q2, when the voltage of the load circuit exceeds the rated highest voltage, the input power supply 28 V_IN is disconnected to input a voltage signal of the load circuit 28 V_OUT, the effect of protecting the load circuit 28 V_OUT is achieved, and as the size of components adopted IN the technical scheme of the embodiment is smaller, the technical scheme is also suitable for small-power protection scenes, the technical problem that the overvoltage protection circuit is limited IN application scenes is effectively solved, and the application requirements under different scenes are realized.
In the description of the present utility model, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "another end," "upper," "one side," "top," "inner," "front," "center," "two ends," etc. indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.
In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "configured," "connected," "secured," "screwed," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intermediaries, or in communication with each other or in interaction with each other, unless explicitly defined otherwise, the meaning of the terms described above in this application will be understood by those of ordinary skill in the art in view of the specific circumstances.
The foregoing is merely a preferred embodiment of the utility model, and it is to be understood that the utility model is not limited to the form disclosed herein but is not to be construed as excluding other embodiments, but is capable of numerous other combinations, modifications and environments and is capable of modifications within the scope of the inventive concept, either as taught or as a matter of routine skill or knowledge in the relevant art. And that modifications and variations which do not depart from the spirit and scope of the utility model are intended to be within the scope of the appended claims.
Claims (9)
1. The overvoltage protection circuit is characterized by comprising a power supply conversion module, a primary amplifying module, a driving control module and an on-off control module;
the power supply conversion module is connected with an input power supply, and is used for converting the input power supply voltage into various reference voltages and providing the reference voltages for the primary amplification module and the drive control module;
the primary amplifying module is connected with the power supply conversion module, the load circuit and the drive control module and is used for comparing the voltage of the load circuit with the reference voltage and providing a comparison result to the drive control module;
the first input end of the driving control module is used for inputting the comparison result, the second input end is used for inputting the reference voltage, the third input end is used for inputting the load circuit voltage, and the output end is connected with the on-off control module;
the first end of the on-off control module is connected with the input power supply, the second end of the on-off control module is connected with the load circuit, and the third end of the on-off control module is connected with the drive control module;
when the voltage of the load circuit is higher than the rated highest voltage, the drive control module outputs a control signal for controlling the on-off control module to disconnect the input power supply from the load circuit;
when the voltage of the load circuit is higher than the threshold voltage, the drive control module outputs a control signal for controlling the on-off control module to reduce the voltage of the load circuit.
2. The overvoltage protection circuit of claim 1, wherein the power conversion module comprises:
a power supply circuit for supplying a constant voltage to the drive control module;
and the voltage conversion circuit is connected with the power supply circuit, the primary amplifying module and the driving control module, and is used for converting the constant voltage into a reference voltage and providing the reference voltage for the primary amplifying module and the driving control module.
3. The overvoltage protection circuit according to claim 2, wherein the power supply circuit comprises a power conversion chip U3, a resistor R10, an inductance L2, and a diode D4;
the inductor L2 is connected in series between the input power supply and the positive electrode of the diode D4, and the negative electrode of the diode D4 is connected with the output end of the power supply circuit;
the power supply pin VIN of the power supply conversion chip U3 is connected with the input power supply, the enabling pin SHDN is connected with the input power supply through a resistor R10, the output pin SW is connected between the inductor L2 and the anode of the diode D4, the grounding pin GND is grounded, and the feedback pin FB is used for inputting the output end voltage of the power supply circuit.
4. The overvoltage protection circuit according to claim 2 or 3, wherein the voltage conversion circuit comprises a resistor R17, a resistor R20, a resistor R21, and a voltage regulator Q5;
the resistor R17, the resistor R20 and the resistor R21 are sequentially connected in series between the output end and the grounding end of the power supply circuit;
the sampling end 1 of the voltage regulator Q5 is connected with the common end of the resistor R20 and the resistor R21, and the control end 2 is connected with the common end of the resistor R17 and the resistor R20;
the common terminal of the resistor R20 and the control terminal 2 of the voltage regulator Q5 is used as an output terminal of the voltage conversion circuit for outputting the reference voltage.
5. The overvoltage protection circuit of claim 4, wherein the primary amplification module comprises an operational amplifier OP1, a resistor R11, a resistor R12, a resistor R13, a resistor R16, a capacitor C5, and a capacitor C7;
the resistor R11 and the resistor R13 are sequentially connected in series between the load circuit and the grounding end;
the power end of the operational amplifier OP1 is connected with the output end of the voltage conversion circuit, the ground is grounded, the non-inverting input end of the operational amplifier OP1 is connected with the output end of the voltage conversion circuit through the resistor R12, the inverting input end of the operational amplifier OP1 is connected with the common end of the resistor R11 and the resistor R13, and the output end of the operational amplifier OP is connected with the driving control module through the resistor R16;
the capacitor C5 is connected between the output end of the voltage conversion circuit and the grounding end;
the capacitor C7 is connected between the output terminal of the operational amplifier OP1 and the ground terminal.
6. The overvoltage protection circuit of claim 5, wherein the drive control module includes a feedback circuit and a control circuit;
the feedback circuit is connected with the load circuit, the voltage conversion circuit and the control circuit and is used for outputting a high level to the control circuit when the voltage of the load circuit is higher than the rated highest voltage and outputting a low level to the control circuit when the voltage of the load circuit is lower than the rated highest voltage;
the control circuit is connected with the power supply circuit, the feedback circuit, the primary amplifying module and the on-off control module and is used for inputting a low level to the on-off control module when the voltage of the load circuit is higher than the rated highest voltage and inputting a high level to the on-off control module when the voltage of the load circuit is higher than the threshold voltage.
7. The overvoltage protection circuit of claim 6, wherein the feedback circuit comprises a resistor R24, a resistor R27, a resistor R28, a resistor R29, a transistor Q6, and a transistor Q7;
the resistor R24 and the resistor R27 are sequentially connected in series between the grounding end and the load circuit;
the base electrode of the triode Q6 is connected with the common end of the resistor R24 and the resistor R27, the emitter electrode is grounded, the collector electrode is connected with one end of the resistor R28, and the other end of the resistor R28 is connected with the voltage conversion circuit;
the base electrode of the triode Q7 is connected with the resistor R28 and the common end of the collector electrode of the triode Q6 and the resistor R28, the emitter electrode is connected with one end of the resistor R29, the collector electrode is connected with the control circuit, and the other end of the resistor R29 is connected with the voltage conversion circuit.
8. The overvoltage protection circuit of claim 7, wherein the control circuit comprises an operational amplifier OP2, a resistor R22, a resistor R25, a resistor R26, a resistor R30, a capacitor C9, and a capacitor C10;
the power end of the operational amplifier OP2 is connected with the output end of the power circuit, the ground is grounded, the non-inverting input end of the operational amplifier OP2 is connected with the primary amplifying module through the resistor R25, the output end of the operational amplifier OP2 is connected with the on-off control module through the resistor R30, the resistor R12 and the resistor R26 are sequentially connected in series between the output end of the operational amplifier OP2 and the ground, and the inverting input end of the operational amplifier OP2 is connected with the common end of the resistor R12 and the resistor R26;
one end of the capacitor C9 is connected between the output end of the power supply circuit and the grounding end;
the capacitor C10 is connected between the output terminal of the operational amplifier OP2 and the ground terminal.
9. The overvoltage protection circuit of claim 8, wherein the on-off control module employs a field effect transistor Q2, a drain of the field effect transistor Q2 is used as a first terminal of the on-off control module, a source of the field effect transistor Q2 is used as a second terminal of the on-off control module, and a gate of the field effect transistor Q2 is used as a third terminal of the on-off control module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202323472672.6U CN220368462U (en) | 2023-12-20 | 2023-12-20 | Overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202323472672.6U CN220368462U (en) | 2023-12-20 | 2023-12-20 | Overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220368462U true CN220368462U (en) | 2024-01-19 |
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ID=89512386
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202323472672.6U Active CN220368462U (en) | 2023-12-20 | 2023-12-20 | Overvoltage protection circuit |
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| Country | Link |
|---|---|
| CN (1) | CN220368462U (en) |
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2023
- 2023-12-20 CN CN202323472672.6U patent/CN220368462U/en active Active
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